arch/x86/include/asm/thread_info.h

   1 /* thread_info.h: low-level thread information
   2  *
   3  * Copyright (C) 2002  David Howells (dhowells@redhat.com)
   4  * - Incorporating suggestions made by Linus Torvalds and Dave Miller
   5  */
   6
   7 #ifndef _ASM_X86_THREAD_INFO_H
   8 #define _ASM_X86_THREAD_INFO_H
   9
  10 #include <linux/compiler.h>
  11 #include <asm/page.h>
  12 #include <asm/types.h>
  13
  14 /*
  15  * low level task data that entry.S needs immediate access to
  16  * - this struct should fit entirely inside of one cache line
  17  * - this struct shares the supervisor stack pages
  18  */
  19 #ifndef __ASSEMBLY__
  20 struct task_struct;
  21 struct exec_domain;
  22 #include <asm/processor.h>
  23 #include <asm/ftrace.h>
  24 #include <linux/atomic.h>
  25
  26 struct thread_info {
  27         struct task_struct      *task;          /* main task structure */
  28         struct exec_domain      *exec_domain;   /* execution domain */
  29         __u32                   flags;          /* low level flags */
  30         __u32                   status;         /* thread synchronous flags */
  31         __u32                   cpu;            /* current CPU */
  32         int                     preempt_count;  /* 0 => preemptable,
  33                                                    <0 => BUG */
  34         mm_segment_t            addr_limit;
  35         struct restart_block    restart_block;
  36         void __user             *sysenter_return;
  37 #ifdef CONFIG_X86_32
  38         unsigned long           previous_esp;   /* ESP of the previous stack in
  39                                                    case of nested (IRQ) stacks
  40                                                 */
  41         __u8                    supervisor_stack[0];
  42 #endif
  43         unsigned int            sig_on_uaccess_error:1;
  44         unsigned int            uaccess_err:1;  /* uaccess failed */
  45 };
  46
  47 #define INIT_THREAD_INFO(tsk)                   \
  48 {                                               \
  49         .task           = &tsk,                 \
  50         .exec_domain    = &default_exec_domain, \
  51         .flags          = 0,                    \
  52         .cpu            = 0,                    \
  53         .preempt_count  = INIT_PREEMPT_COUNT,   \
  54         .addr_limit     = KERNEL_DS,            \
  55         .restart_block = {                      \
  56                 .fn = do_no_restart_syscall,    \
  57         },                                      \
  58 }
  59
  60 #define init_thread_info        (init_thread_union.thread_info)
  61 #define init_stack              (init_thread_union.stack)
  62
  63 #else /* !__ASSEMBLY__ */
  64
  65 #include <asm/asm-offsets.h>
  66
  67 #endif
  68
  69 /*
  70  * thread information flags
  71  * - these are process state flags that various assembly files
  72  *   may need to access
  73  * - pending work-to-be-done flags are in LSW
  74  * - other flags in MSW
  75  * Warning: layout of LSW is hardcoded in entry.S
  76  */
  77 #define TIF_SYSCALL_TRACE       0       /* syscall trace active */
  78 #define TIF_NOTIFY_RESUME       1       /* callback before returning to user */
  79 #define TIF_SIGPENDING          2       /* signal pending */
  80 #define TIF_NEED_RESCHED        3       /* rescheduling necessary */
  81 #define TIF_SINGLESTEP          4       /* reenable singlestep on user return*/
  82 #define TIF_IRET                5       /* force IRET */
  83 #define TIF_SYSCALL_EMU         6       /* syscall emulation active */
  84 #define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
  85 #define TIF_SECCOMP             8       /* secure computing */
  86 #define TIF_MCE_NOTIFY          10      /* notify userspace of an MCE */
  87 #define TIF_USER_RETURN_NOTIFY  11      /* notify kernel of userspace return */
  88 #define TIF_NOTSC               16      /* TSC is not accessible in userland */
  89 #define TIF_IA32                17      /* 32bit process */
  90 #define TIF_FORK                18      /* ret_from_fork */
  91 #define TIF_MEMDIE              20      /* is terminating due to OOM killer */
  92 #define TIF_DEBUG               21      /* uses debug registers */
  93 #define TIF_IO_BITMAP           22      /* uses I/O bitmap */
  94 #define TIF_FORCED_TF           24      /* true if TF in eflags artificially */
  95 #define TIF_BLOCKSTEP           25      /* set when we want DEBUGCTLMSR_BTF */
  96 #define TIF_LAZY_MMU_UPDATES    27      /* task is updating the mmu lazily */
  97 #define TIF_SYSCALL_TRACEPOINT  28      /* syscall tracepoint instrumentation */
  98
  99 #define _TIF_SYSCALL_TRACE      (1 << TIF_SYSCALL_TRACE)
 100 #define _TIF_NOTIFY_RESUME      (1 << TIF_NOTIFY_RESUME)
 101 #define _TIF_SIGPENDING         (1 << TIF_SIGPENDING)
 102 #define _TIF_SINGLESTEP         (1 << TIF_SINGLESTEP)
 103 #define _TIF_NEED_RESCHED       (1 << TIF_NEED_RESCHED)
 104 #define _TIF_IRET               (1 << TIF_IRET)
 105 #define _TIF_SYSCALL_EMU        (1 << TIF_SYSCALL_EMU)
 106 #define _TIF_SYSCALL_AUDIT      (1 << TIF_SYSCALL_AUDIT)
 107 #define _TIF_SECCOMP            (1 << TIF_SECCOMP)
 108 #define _TIF_MCE_NOTIFY         (1 << TIF_MCE_NOTIFY)
 109 #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
 110 #define _TIF_NOTSC              (1 << TIF_NOTSC)
 111 #define _TIF_IA32               (1 << TIF_IA32)
 112 #define _TIF_FORK               (1 << TIF_FORK)
 113 #define _TIF_DEBUG              (1 << TIF_DEBUG)
 114 #define _TIF_IO_BITMAP          (1 << TIF_IO_BITMAP)
 115 #define _TIF_FORCED_TF          (1 << TIF_FORCED_TF)
 116 #define _TIF_BLOCKSTEP          (1 << TIF_BLOCKSTEP)
 117 #define _TIF_LAZY_MMU_UPDATES   (1 << TIF_LAZY_MMU_UPDATES)
 118 #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
 119
 120 /* work to do in syscall_trace_enter() */
 121 #define _TIF_WORK_SYSCALL_ENTRY \
 122         (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT |   \
 123          _TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT)
 124
 125 /* work to do in syscall_trace_leave() */
 126 #define _TIF_WORK_SYSCALL_EXIT  \
 127         (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP |    \
 128          _TIF_SYSCALL_TRACEPOINT)
 129
 130 /* work to do on interrupt/exception return */
 131 #define _TIF_WORK_MASK                                                  \
 132         (0x0000FFFF &                                                   \
 133          ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|                       \
 134            _TIF_SINGLESTEP|_TIF_SECCOMP|_TIF_SYSCALL_EMU))
 135
 136 /* work to do on any return to user space */
 137 #define _TIF_ALLWORK_MASK                                               \
 138         ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT)
 139
 140 /* Only used for 64 bit */
 141 #define _TIF_DO_NOTIFY_MASK                                             \
 142         (_TIF_SIGPENDING | _TIF_MCE_NOTIFY | _TIF_NOTIFY_RESUME |       \
 143          _TIF_USER_RETURN_NOTIFY)
 144
 145 /* flags to check in __switch_to() */
 146 #define _TIF_WORK_CTXSW                                                 \
 147         (_TIF_IO_BITMAP|_TIF_NOTSC|_TIF_BLOCKSTEP)
 148
 149 #define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY)
 150 #define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW|_TIF_DEBUG)
 151
 152 #define PREEMPT_ACTIVE          0x10000000
 153
 154 /* thread information allocation */
 155 #ifdef CONFIG_DEBUG_STACK_USAGE
 156 #define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO)
 157 #else
 158 #define THREAD_FLAGS (GFP_KERNEL | __GFP_NOTRACK)
 159 #endif
 160
 161 #define __HAVE_ARCH_THREAD_INFO_ALLOCATOR
 162
 163 #define alloc_thread_info_node(tsk, node)                               \
 164 ({                                                                      \
 165         struct page *page = alloc_pages_node(node, THREAD_FLAGS,        \
 166                                              THREAD_ORDER);             \
 167         struct thread_info *ret = page ? page_address(page) : NULL;     \
 168                                                                         \
 169         ret;                                                            \
 170 })
 171
 172 #ifdef CONFIG_X86_32
 173
 174 #define STACK_WARN      (THREAD_SIZE/8)
 175 /*
 176  * macros/functions for gaining access to the thread information structure
 177  *
 178  * preempt_count needs to be 1 initially, until the scheduler is functional.
 179  */
 180 #ifndef __ASSEMBLY__
 181
 182
 183 /* how to get the current stack pointer from C */
 184 register unsigned long current_stack_pointer asm("esp") __used;
 185
 186 /* how to get the thread information struct from C */
 187 static inline struct thread_info *current_thread_info(void)
 188 {
 189         return (struct thread_info *)
 190                 (current_stack_pointer & ~(THREAD_SIZE - 1));
 191 }
 192
 193 #else /* !__ASSEMBLY__ */
 194
 195 /* how to get the thread information struct from ASM */
 196 #define GET_THREAD_INFO(reg)     \
 197         movl $-THREAD_SIZE, reg; \
 198         andl %esp, reg
 199
 200 /* use this one if reg already contains %esp */
 201 #define GET_THREAD_INFO_WITH_ESP(reg) \
 202         andl $-THREAD_SIZE, reg
 203
 204 #endif
 205
 206 #else /* X86_32 */
 207
 208 #include <asm/percpu.h>
 209 #define KERNEL_STACK_OFFSET (5*8)
 210
 211 /*
 212  * macros/functions for gaining access to the thread information structure
 213  * preempt_count needs to be 1 initially, until the scheduler is functional.
 214  */
 215 #ifndef __ASSEMBLY__
 216 DECLARE_PER_CPU(unsigned long, kernel_stack);
 217
 218 static inline struct thread_info *current_thread_info(void)
 219 {
 220         struct thread_info *ti;
 221         ti = (void *)(percpu_read_stable(kernel_stack) +
 222                       KERNEL_STACK_OFFSET - THREAD_SIZE);
 223         return ti;
 224 }
 225
 226 #else /* !__ASSEMBLY__ */
 227
 228 /* how to get the thread information struct from ASM */
 229 #define GET_THREAD_INFO(reg) \
 230         movq PER_CPU_VAR(kernel_stack),reg ; \
 231         subq $(THREAD_SIZE-KERNEL_STACK_OFFSET),reg
 232
 233 /*
 234  * Same if PER_CPU_VAR(kernel_stack) is, perhaps with some offset, already in
 235  * a certain register (to be used in assembler memory operands).
 236  */
 237 #define THREAD_INFO(reg, off) KERNEL_STACK_OFFSET+(off)-THREAD_SIZE(reg)
 238
 239 #endif
 240
 241 #endif /* !X86_32 */
 242
 243 /*
 244  * Thread-synchronous status.
 245  *
 246  * This is different from the flags in that nobody else
 247  * ever touches our thread-synchronous status, so we don't
 248  * have to worry about atomic accesses.
 249  */
 250 #define TS_COMPAT               0x0002  /* 32bit syscall active (64BIT)*/
 251 #define TS_POLLING              0x0004  /* idle task polling need_resched,
 252                                            skip sending interrupt */
 253 #define TS_RESTORE_SIGMASK      0x0008  /* restore signal mask in do_signal() */
 254
 255 #define tsk_is_polling(t) (task_thread_info(t)->status & TS_POLLING)
 256
 257 #ifndef __ASSEMBLY__
 258 #define HAVE_SET_RESTORE_SIGMASK        1
 259 static inline void set_restore_sigmask(void)
 260 {
 261         struct thread_info *ti = current_thread_info();
 262         ti->status |= TS_RESTORE_SIGMASK;
 263         set_bit(TIF_SIGPENDING, (unsigned long *)&ti->flags);
 264 }
 265 #endif  /* !__ASSEMBLY__ */
 266
 267 #ifndef __ASSEMBLY__
 268 extern void arch_task_cache_init(void);
 269 extern void free_thread_info(struct thread_info *ti);
 270 extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
 271 #define arch_task_cache_init arch_task_cache_init
 272 #endif
 273 #endif /* _ASM_X86_THREAD_INFO_H */